Modem aircraft are increasingly complex. The complexities of these aircraft have led to an increasing need for automated fault detection systems. These fault detection systems are designed to monitor the various systems of the aircraft in an effect to detect potential faults. These systems are designed to detect these potential faults such that the potential faults can be addressed before the potential faults lead to serious system failure and possible in-flight shutdowns, take-off aborts, and delays or cancellations.
Turbine engines, including main power and auxiliary power engines are of course, a particularly critical part of the aircraft. As such, fault detection for turbine engines are an important part of an aircraft's fault detection system. One area where fault detection has been lacking is in transient conditions such as during startup of a turbine engine. One problem with fault detection during startup has been the inability of fault detection systems to accurately and reliably determine when the various conditions in engine startup have occurred, such as lightoff and engine idle. During startup of a turbine engine, a starter motor rotates the turbine engine while the combustor provides fuel that is ignited by the igniter. Engine lightoff is defined as the time when combustion has been initiated and the engine itself begins to provide torque, as opposed to being driven solely by the starter. The engine then continues to increase in speed until full idle speed is reached.
Without an accurate determination of when these conditions occur it is difficult to compare measurements from multiple startups of a given engine or large engine sample under varying ambient conditions and with varying component health states, and thus difficult to trend or otherwise detect faults that are or will be occurring in the turbine engine.
Another problem with fault detection during startup has been the large amounts of data typically required to analyze the performance of the engine during startup. In many cases such large amounts of data cannot be reasonably stored and passed to the fault detection system due to limitations in hardware. This again has limited the ability of fault detection and control systems.